RELEASE, OXIDATION, AND REESTERIFICATION OF FATTY-ACIDS FROM INFUSED TRIGLYCERIDES - EFFECT OF HEPARIN

We have investigated the effects of heparin on rates of fatty acid (FA ) release, oxidation, and reesterification from intravenously (IV) inf used triglycerides (TGs) during euglycemic (4.7 mmol . L(-1)) hyperins ulinemia (similar to 450 pmol . L(-1)). Four healthy men (aged 31 +/- 3 years; body mass index, 26.1 +/- 0.9 kg/m(2)) received IV TGs (1.02 mmol TG . kg(-1). 4 h(-1)), four other men (aged 24.3 +/- 2.8 years; b ody mass index, 24.7 +/- 1.7 kg/m(2)) received TGs plus heparin (200-U bolus followed by 0.4 U . kg(-1). min(-1)), and nine men and one woma n (aged 28.8 +/- 2.3 years; body mass index, 23.1 +/- 0.9 kg/m(2)) rec eived saline (controls). Heparin increased lipolysis from infused TGs (to 1.0 +/- 0.1 from 0.3 +/- 0.1 mmol . kg(-1). 4 h(-1), P <.01), incr eased plasma free fatty acids ([FFA] to 737 +/- 32 from 597 +/- 136 mu mol . L(-1), P <.05), and increased FA reesterification (to 0.84 +/- 0.14 from 0.18 +/- 0.12 mmol . kg(-1). 4 h(-1), P <.02), but had no ef fect on FA oxidation (0.13 +/- 0.02 v 0.12 +/- 0.04 mmol . kg(-1). 4 h (-1)) or net energy gain (167 +/- 42 v 243 +/- 79 kJ . 4 h(-1)). In su mmary, addition of heparin (1) increased lipolysis (to similar to 98% from similar to 29%) and reesterification (to similar to 82% from simi lar to 17%) of infused TG, but had no significant effects on fat oxida tion (similar to 12%) and net energy gain. We conclude that heparin ac celerated removal of infused lipid from the blood and its deposition i nto endogenous fat depots. Since the doses of heparin and insulin used in this study were higher than those generally used in total parenter al nutrition protocols, our results may not be strictly applicable to the usual clinical situation. Copyright (C) 1995 by W.B. Saunders Comp any